Bayonet lock cannula for pre-slit y-site

ABSTRACT

A cannula and injection site coupling system comprising a cannula assembly having a blunt cannula or piercing member partially surrounded by a protective shield. The protective shield is spaced apart from the blunt cannula and includes a bayonet arm, a bayonet barb, a bayonet lock and an opening or gap. The injection site has a septum with a pre-slit opening and an arm. When the cannula assembly and injection site are coupled, the injection site arm is lodged within the cannula assembly lock opening.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation, of application Ser. No. 08/021,644,filed Feb. 22, 1993, now abandoned, which is a continuation, ofapplication Ser. No. 07/435,638, filed Nov. 9, 1989, now abandoned,which is a continuation-in-part application of the commonly assignedU.S. patent application, Ser. No. 217,004 entitled "Pre-Slit InjectionSite and Tapered Cannuala" filed Jul. 8, 1988, now abandoned, which is acontinuation-in-part application of the commonly assigned U.S. patentapplication, Ser. No. 147,414 entitled "Pre-Slit Injection Site andAssociated Cannula" filed Jan. 25, 1988, now abandoned. Both patentapplications are herein incorporated by reference and made part of thispatent application as though they were reproduced completely herein.

FIELD OF THE INVENTION

The invention pertains to coupling systems usable to transfer materialsfrom one flow conduit to another. More particularly, the inventionpertains to two-part coupling members with a first part including apre-slit septum and a second part including a blunt cannula at leastpartially surrounded by a protective shield. The pre-slit septumslidably receives the blunt cannula to effect the coupling. The systemshave particular applicability in the medical field for handlingmedications and body fluids.

BACKGROUND OF THE INVENTION

In the medical field, injection sites usable with pointed cannulae havelong been known. For example, such sites can be formed with a housinghaving a fluid flow path therein. A septum is positioned in the housingclosing the fluid flow path.

One injection site usable with a piercing cannula is disclosed in U.S.Pat. No. 4,412,573 to Zdeb entitled "Injection Site." The Zdeb patent isassigned to Assignee of the present invention.

The pointed cannula can be forced through the septum into fluid flowcommunication with the flow path in the housing. Known injection sitesusable with a piercing cannula can be physically damaged by repetitivepiercing caused by the sharp cannula. This damage, known as coring orlaceration, can result in subsequent leakage.

Due to problems associated with infectious agents, personnel using suchpointed cannulae do so with great care. Notwithstanding careful andprudent practice, from time to time, accidents do occur and individualsusing such pointed cannulae jab themselves.

Injection sites usable with a blunt cannula are also known. For example,U.S. Pat. No. 4,197,848 issued to Garrett et al. entitled "ClosedUrinary Irrigation Site" and assigned to the Assignee of the presentinvention discloses one such injection site. That injection site is arelatively low pressure device having a relatively thin, molded, sealingmember. The sealing member has an opening therethrough.

A blunt cannula can be forced through the sealing member placing thecannula into fluid flow communication with a fluid flow pathway in theinjection site.

Injection sites of the type noted above usable with a blunt cannula havethe advantage that the blunt cannula will not pierce the skin of a user.On the other hand, it is important that the pre-slit injection sitereseal with enough force that fluids do not ooze therefrom and thatairborne particulate matter, bacterial or viral matter do not entertherethrough.

Hence, there continues to be a need for a pre-slit injection site whichcan be used with a variety of solutions and over a range of fluidpressures. Further, there continues to be a need for such a pre-slitinjection site which will reliably reseal even after many insertions ofthe blunt cannula.

Such an injection site should be able to receive a large number ofinsertions of the cannula without displaying reseal failure and withoutallowing the cannula to drop out of contact. Such an injection siteshould provide for improved alignment of the cannula on insertion.Improved alignment will result in less chance of damage to the injectionsite after repeated insertions of the cannula. Preferably, the injectionsite would also be usable with a pointed cannula. Preferably, a pre-slitinjection site usable with a blunt cannula will provide a reasonablelevel of insertion force such that health care personnel will readily beable to insert the blunt cannula, yet the cannula will not easily fallfrom or drop out of contact with the septum.

SUMMARY OF THE INVENTION

In accordance with the invention, an easily wipeable Y-type injectionsite or Y-site usable with a bayonet lock cannula is provided.

The bayonet lock cannula includes a blunt cannula which may be ofseveral designs surrounded by a protective shield. The protective shieldincludes an arcuate wall with a bayonet arm and barb to provide abayonet lock. As the bayonet lock cannula is inserted onto the Y-site,the Y-site arm passes through the gap between the bayonet arm and thearcuate wall. Both the bayonet lock cannula and the Y-site havedimensions to create four zones of interference. These zones ofinterference properly align the Y-site and bayonet lock cannula withrespect to one another so that the piercing member will be perpendicularto the Y-site septum or sealing member.

The injection site includes a housing which defines a fluid flow channeltherethrough. The housing has a first and a second end.

A flexible sealing member is carried by the housing for sealing thefirst end. The sealing member has a resealable opening therein. Thesealing member also is formed with a curved exterior peripheral surfacesuch that the blunt cannula can be sealingly inserted through theopening and placed in fluid flow communication with the flow path.Further, the blunt cannula can be removed from the opening with thesealing member then interacting with the housing so as to reseal theopening.

The housing can also be formed with the first end including an annularchannel underlying the sealing member. The sealing member is subjectedto radially directed forces by a tapered surface of the first end of thehousing. These forces tend to reseal the opening in the sealing member.

The sealing member can be a cylindrically shaped rubber member. Thefirst end of the housing can include an interior tapered surface forreceiving the sealing member and for applying the radially directedforces to the sealing member.

A retaining member carried by the first end of the housing can be usedto retain the sealing member with the housing. The retaining member canbe generally U-shaped. Alternately, the retaining member can be formedas a coiled spring.

The retaining member applies axially directed forces to the sealingmember. In one embodiment of the invention, the retaining memberdeflects the sealing member and forms a cured exterior peripheralsurface thereon. The curved exterior peripheral surface is an easilywipeable surface.

The retaining member deflects or distorts the upper and lower peripheraledges slightly as a result of applying axial forces thereto. When theblunt piercing member is inserted into the slit in the sealing member,an annular interior peripheral region of the sealing member deformsfurther and fills, at least in part, the annular channel.

Deformation of this annular peripheral region results in an insertionforce in a range of 2.0 to 5 pounds. Preferably, the insertion forcewill have a value of the order of 2.0 pounds.

The resealable opening in the sealing member can extend entirely throughthat member. Alternately, the resealable opening can extend only partwaytherethrough. In this embodiment, the end of the blunt cannula will beused to tear through the remainder of the sealing member.

The sealing member can be formed in two parts. An exterior cylindricalportion can be slit completely. An interior cylindrical unslit portioncan be provided to seal the site until the blunt cannula is insertedtherethrough the first time.

The interior surface of the first end can be formed with the taper in arange on the order of 5 degrees to 20 degrees. Preferably, the interiorsurface will have a taper on the order of 12 degrees. This taperedsurface permits the use of a cylindrically shaped sealing member.

To provide for leak-free insertion, the length of the slit in thesealing member must be less than one-half of the circumference of thecannula being inserted therethrough. Hence, the slit length may exceedthe diameter of the cannula being inserted. In addition, the slit lengthmust be great enough, given the elastic limit of the sealing member, toprevent tearing during insertion.

Further in accordance with the invention, a coupling system for couplingfirst and second fluid flow members together is provided. The couplingsystem includes an injection site which is affixed to the first fluidflow member. The injection site includes a housing. The housing has afluid flow path therethrough.

A sealing member is carried by the housing. The sealing member has aresealable opening therein.

An annular retaining member is carried by the housing and cooperateswith the housing to retain the sealing member therein. Radially directedforces are applied to the sealing member by the housing, thereby urgingthe opening into a resealed condition.

A blunt cannula, affixed to a second fluid flow member, has a fluid flowpath therethrough. The cannula engages the housing when the cannulaextends through the opening of the sealing member. When so positioned,the two fluid flow members are placed into fluid flow communication.

Numerous other advantages and features of the present invention willbecome readily apparent from the following detailed description of theinvention and the embodiments thereof, from the claims and from theaccompanying drawings in which the details of the invention are fullyand completely disclosed as a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view, partly in section, of a prior artpre-slit injection site and an associated blunt cannula;

FIG. 2 is an overall view of a container, an associated solutionadministration set and a pre-slit injection Y-site in accordance withthe present invention;

FIG. 3 is a side view of the Y-site connector in section carrying apre-slit injection site in accordance with the present invention;

FIG. 4 is an enlarged fragmentary side view in section of a couplingmember carrying a pre-slit injection site where the slit extends onlypartway through the septum;

FIG. 5 is a perspective view of a blunt cannula with lever lockingmembers prior to engaging the pre-slit septum of an injection site.

FIG. 6 is a perspective view of a pre-slit Y-site and bayonet lockcannula bounded to tubing.

FIG. 7 is an exploded perspective view of a pre-slit Y-site and bayonetlock cannula with a luer lock connection to tubing.

FIG. 8 is a perspective view of a bayonet lock cannula having twobayonet locks.

FIG. 9 is a side view in section of the bayonet lock cannula.

FIG. 10 is a perspective view with a partial sectional of the pre-slitY-site with bayonet lock cannula.

FIG. 11 is a side view of the pre-slit Y-site with bayonet lock cannula.

FIG. 12 is a top view of the bayonet lock cannula with a luer lockconnection.

FIG. 13 is a side sectional view of the pre-slit Y-site with bayonetlock cannula in the locked position.

FIG. 14 is a sectional view of a first embodiment of a blunt cannula.

FIG. 15 is a top view of the blunt cannula of FIG. 14.

FIG. 16 is a second embodiment of a blunt cannula.

FIG. 17 is a top view of the blunt cannula of FIG. 16.

FIG. 18 is a third embodiment of a blunt cannula.

FIG. 19 is a schematic exploded side view of the pre-slit Y-site andbayonet lock cannula with zones of interference marked.

FIG. 20 is a step in the method of making a pre-slit injection site inaccordance with the present invention.

FIG. 21 is another step in the method of making a pre-slit injectionsite in accordance with the present invention.

FIG. 22 is an initial phase of a final step in making a pre-slitinjection site in accordance with the present invention.

FIG. 23 is an intermediate phase of the final step in a method of makinga pre-slit injection site in accordance with the present invention.

FIG. 24 is a final phase of the final step in a method of making apre-slit injection site in accordance with the present invention.

FIG. 25 illustrates an initial phase in an alternate step of making apre-slit injection site in accordance with the present invention.

FIG. 26 illustrates a final phase of the alternate step in a method ofmaking an injection site in accordance with the present invention.

FIG. 27 illustrates yet another alternate step in a method of making apre-slit injection site in accordance with the present invention.

FIG. 28 is an enlarged, fragmentary cross-sectional view of anotherembodiment of an injection site in accordance with the presentinvention.

FIG. 29 is a cross-section view taken generally along the plane 29--29in FIG. 28.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

While this invention is susceptible of embodiment in many differentforms, there are shown in the drawings and will be described herein indetail specific embodiments thereof with the understanding that thepresent disclosure is to be considered as an exemplification of theprinciples of the invention and is not intended to limit the inventionto the specific embodiments illustrated.

A prior art pre-slit injection site 10 and associated blunt cannula 12are illustrated in FIG. 1. The prior art injection site 10 has acylindrical housing 14 with a fluid flow path 16 therethrough. A firstend 18 of the housing 14 is closed with a relatively thin disc-shapedresealable member 20. The member 20 has a resealable opening 22 therein.

The member 20 is a molded septum with an integrally formed skirt 20a.The skirt 20a is oriented generally perpendicular to the portion of theseptum with the opening 22.

The cannula 12 includes a body portion 24 which carries at a first end ahollow, cylindrical, blunt piercing member 26. As the cannula 12 ismoved in a direction 28 toward the first end 18 of the injection site10, the member 26 slidably engages the opening 22. The sealing member 20is then deformed adjacent the opening 22 and the member 26 extends intothe flow path 16. A fluid flow path through the cannula 12 will then bein fluid flow communication with the flow path 16 via the hollowpiercing member 26.

FIGS. 2 and 3 illustrates a pre-slit septum 52 in a Y-site connector orY-site 36 which is connected to first and second pieces of tubing, 38and 40, respectively. FIG. 2 shows a fluid administration set 42 of aconventional variety except that it includes as a component the pre-slitY-site 36. The set 42 includes a spike connection 44 at a first enddesigned to pierce the port 46 of the container 48. The set 42 may alsoinclude other components such as adjustable clamps or filters. At thesecond end of the set 42 is a piercing member 50 which connects thefluid flow to the patient, such as through a vein in the hand of thepatient.

As shown in FIG. 3, Y-site 36 is formed with a cylindrical housing 70having a first end 72, and a second end 74 and one arm 76. As discussedabove, the second end 74 is bounded to second tubing 40 and the arm 76is bounded to first tubing 38. The primary flow of fluid is fromcontainer 48 through arm 76 and second end 74 to the patient. Thesecondary fluid flow from a second container, syringe or other medicaldevice (not shown) is through first end 72 and second end 74 to thepatient. The primary fluid and the secondary fluid are mixed in thesecond end 74 of the Y-site housing and in second tubing 40.

FIG. 3 illustrates, in section, further details of the Y-site 36. Aresealable septum 52 is carried by the first end 72 of the housing 70.The septum 52 includes first and second spaced apart surfaces 54 and 56respectively. The surface 54 has been forced into a dome-like shape byannular, U-shaped, swaged end members 58 carried by the first end 72.The dome-like shape of the surface 54 can extend beyond a surface 72a ofthe first end 72. This facilitates cleaning the surface 54.

The septum 52 has a generally cylindrical shape. The septum 52 can beformed of a latex or synthetic rubber material. Alternately, the septumcan be formed of a thermosplastic elastomer. The material used for theseptum 52 should be non-toxic and sterilizable such as by means ofradiation, steam or ethylene oxide.

Because the septum 52 is generally cylindrical in shape, it can bedie-cut from a sheet, cut from an extruded rod or molded. The septum 52can have an exemplary diameter on the order of 0.30 inches. The heightof the septum 52 can be, for example, on the order of 0.125 inches.

The first end 72 is also formed with a tapered interior surface 60 whichterminates in an annular channel 62. The tapered interior surface 60 hasa taper in a range of 5 degrees to 20 degrees. Preferably, the taperwill be on the order of 7 degrees. With the indicated size of the abovenoted exemplary septum 52 and a 7 degree taper, diametric resealingcompression of the septum 52 adjacent the channel 62 is on the order of10%.

The channel 62 is bounded in part by a septum supporting ridge 62a. Thechannel 62 can typically have a depth in a range of 0.050-0.070 inches.

A peripheral surface 64 of the septum 52 slidably engages the taperedinterior surface 60 as the septum 52 slides into the first end 72. Theannular channel 62 which underlies the interior peripheral surface 64 ofthe septum 52 is provided to permit the septum 52 to deform when a bluntcannula is inserted through an opening 66 therein.

The swaged end members 58 apply axial forces to the septum 52 therebycreating the domed exterior peripheral surface 54. The axial forcesapplied by the end members 58 slightly deform the regions 52a and 52b.The tapered internal surface 60 applies radially directed forces to theseptum 52, thereby forcing the opening 66 into a resealed condition.

In an alternate embodiment, the surface 54 could be formed as a flat, asopposed to a domed, surface.

Once the Y-site 36 is lockingly engaged with the bayonet lock cannula82, as will be discussed later, a sealed system is formed through whichfluids can be infused into the Y-site 36. The resealable septum 52closes the fluid flow path through Y-site 36 when the bayonet lockcannula 82 is disengaged.

As discussed in the copending patent applications incorporated byreference, the injection site and blunt cannula may be adapted for usewith a variety of medical instruments, including, but not limited to asyringe with luer locking connection, a blunt cannula with deflectinglever locking members, or a spike connection for an IV solution bag.

In addition to being used with the bayonet locking cannula 82 of FIGS.7-13, the Y-site of the present invention may be also used with avariety of other cannulas, including the blunt cannula 86 of FIG. 5 orthe cannulas shown in FIGS. 14 through 18.

FIG. 5 illustrates the pre-slit injection Y-site used with a bluntcannula 86 to two spring-like deflecting lever arms 100a and 100b. Thecurved end regions 100c of the lever members 100a and 100b slidinglyengage the offset surface 88 of the Y-site 36 after the piercing member98a of the blunt cannula 86 has been forced through the preformedopening.

The cannula shown in FIGS. 14-18 may be used with the Y-site alone, ormay be incorporated into a bayonet locking cannula to achieve a lockedblunt cannula/Y-site connection as will be described later.

FIGS. 14 and 15 illustrate a tapered cannula structure 104 which is afirst embodiment that can be used with the Y-site 36 or may incorporatedinto the bayonet locking cannula 82. The cannula includes a proximal end106 with an interior region 108. The interior region 108 is in partbounded by an internal peripheral wall 110 which is formed with astandard luer taper. The tapered cannula 104 can be formed with aluer-type coupling flange 112 at the proximal end so as to be releasablyconnected to another medical device, such as a syringe.

Extending from the proximal end 106 is a cylindrical tube having acylindrical mid-region 114 and a distal end member 116. The distal endmember 116 has a generally elongated, cylindrical shape with a exteriorside wall 120. A centrally located, cylindrical, internal fluid flowpath 118 extends through distal end member 116 and mid-region 114 andfluid flow communication with the interior region 108. The distal end ofend member 116 has a tapered exterior surface 122. The tapered exteriorsurface 122 minimizes insertion force of the cannula 104 is being forcedthrough a slit of the septum, such as the slit 66 of septum 52. Theangle of taper of the surface 122 is preferably in the range between 1to 15 degrees.

The distal end member 116 is also provided with a plurality of elongatedgrooves 124. The grooves 124 in the exterior wall of the distal endmember 116 decrease the surface area contact at the cannula/septuminterface during insertion of the cannula and to the Y-site 36. Thisreduce exterior contact surface area decreases the frictional componentof the insertion force.

In one embodiment, the tapered blunt cannula 104 may have an overallinsertion length, corresponding to the axial length of mid-region 114and end member 116, on the order of 0.375 inches. An alternate cannulastructure, identified generally as numeral 130, is shown in FIGS. 16 and17. The cannula 130 includes a proximal end 132 defining an interiorregion 134 and having a luer type flange 136 for connection to asuitable mating engaging surface.

A generally cylindrical mid-region 137 extends between the proximal end132 and a distal end region 138. The embodiment of the cannula 130minimizes kick back due recoil or to the provision of substantiallycylindrical mid-region 137. This design also increases tug resistance toreduce inadvertent withdrawal.

A generally cylindrical internal flow channel 140 extends through theend region 138 and mid-region 137 in communication with the interiorregion 134 of the proximal end region 132. The end region 138 isprovided with a tapered surface 142. The design permits of a very smalltaper to minimize the insertion force. Further the design permits thecannula 130 to be constructed with a small tip diameter, small taperedangle and small cannula diameter so as to reduce the peak insertionforce.

Still another embodiment is illustrated in FIG. 18 which shows a blunttapered cannula insertion member 150 for insertion into the pre-slitinjection Y-site. The cannula 150 has a distal end region 152 with atapered exterior surface in which the preferred embodiment is anapproximately 8°. The defined aperture 154 for fluid flow is disposed atthe end region 156 of the distal end region 152. The end 156 includes aradiused tip defined by a radius of approximately 0.01 inch. Theradiused tip reduces insertion force, assist in locating the slit in theinjection site and in addition has the practical advantage offacilitating complete filling of the cannula mold cavity.

The tapered surface of the distal end region 152 has an axial length ofapproximately 0.10 inches in the preferred embodiment. Adjacent to thetapered distal end region is a generally cylindrical region 158 forentering into the injection site behind the distal end region 152,thereby reducing kick back during insertion. The generally cylindricalregion 158 bas a small draft angle such as about one-half degree.

The force required to insert any of the above-discussed embodiments of ablunt tapered cannula into the septum of the injection site depends upona number of factors: friction at the cannula/septum interface, cannuladiameter, cannula tapered angle, and degree of septum compression. Thecannula/septum interface friction is, in turn, dependent uponlubrication, if any, material properties and surface finish. It will beunderstood that the friction at the cannula/septum interface can bereduced by providing a smoother surface finish on the cannula (e.g., bysandblasting the cannula exterior surface) or by molding the cannula soas to produce a matte finish. Conventional lubricants can also be usedto further reduce friction and thereby lower the insertion forcerequired.

The deformation of the septum 52 also facilitates insertion of thepiercing member 98 through the slit 66. Subsequent to the piercingmember 98 slidably engaging the Y-type injection site or Y-site 36, theinterior region of the tubing 192 to which the bayonet locking cannula82 is connected is in fluid flow communication with the flow path 68 ofthe Y-site 36 via the flow path of the blunt piercing member 98.

In this engagement condition, the septum 52 seals completely around thepiercing member 84. Hence, exterior gases, liquids or airborne matterwill be excluded from the flow path 68.

Subsequent to infusing fluid from the bayonet locking cannula 82 intothe fluid flow pathway 68, hence to the patient, the bayonet lockingcannula 82 with lockingly engaged shielded cannula 86 can be slidablywithdrawn from the injection site 34. Subsequent to this withdrawal, theseptum 52 reseals the opening or slit 53 therein.

The opening 53 will repeatedly reseal, when the piercing member 98 isremoved, provided that the pressure (in the septum 52) created byinteraction of the septum material properties and compression suppliedby the housing exceeds the pressure challenge of the fluid containedwithin. Blunt cannula do not haphazardly core, lacerate, or otherwisedamage the sealing interface of slit 53 as conventional needles do,thereby allowing repeatable resealability. However, septum materialproperties, thickness, and compression allow resealability for a finitenumber of conventional needle insertions. The Y-site 36 then returns toits pre-infusion, sealed condition.

As an alternate to forming the slit 66 completely through the septum 52,as illustrated in FIG. 4 a slit 53a can be formed only partly throughthe septum 52. Such a structure has the further advantage that untilused for the first time the septum 52 is completely sealed.

The septum 52 can be formed in two parts. One part can have a slit, suchas the slit 66 extending entirely therethrough. A second part can beformed without a slit. These two parts can be located adjacent oneanother in first end 72 of the injection site.

The slit 66a may be longer on the top of the septum than the bottom.This feature aids blunt cannula alignment with the slit upon insertion,and aids resealability by minimizing the critical slit sealing interfacearea.

In accordance with the present invention, the slit 66 could have alength with a range on the order of 0.03 to 0.150 inches. Preferably, aslit length in the order of 0.07 inches will be used in combination witha blunt cannula having a diameter on the order of 0.1 inches.

When initially used, the blunt cannula piercing member 98 will be forcedthrough the slit 66a. The lower peripheral surface 52 will then bepunctured, providing access for the blunt cannula piercing member 98into the fluid flow pathway 68.

FIGS. 20-24 disclose a method of making a pre-slit injection site inaccordance with the present invention. In a first step, a housing 200 isprovided. The housing 200 has an interior tapered surface 202 at a firstend 200a thereof. The interior peripheral surface terminates in anannular channel 204. A cylindrical septum 206 can be provided adjacentthe end 200a.

In a second step, the septum 206 can be forced into the end 200c of thehousing 200o and slightly deformed by the tapered peripheral surface 202using an axially moving die 210. When positioned by the die 210, theseptum 206 is located adjacent an internal annular ring 212 which boundsthe annular channel 204.

In a third step, a second die 214 can be utilized to swag the end 200ainto spiral-shaped, spring-like members 200b which apply axiallydirected forces against an exterior peripheral surface 206a of theseptum 206. The axially directed forces form the flat surface 206a intoa domed exterior peripheral surface 206b as illustrated in FIG. 23.

Simultaneously, with swaging the end members 200a so as to lock theseptum 206 into the housing 200 and to form the domed exteriorperipheral surface 206b, a knife 216 can be utilized to form a slit inthe septum 206. Alternatively, the slit may be cut by a separate die ina separate step. If the septum 206 is formed as an extrusion, the slitcan be created during the extrusion process. If the septum 206 is formedby stamping from a rubber sheet, the slit can be cut during the stampingprocess. If the septum 206 is formed by compression molding, the slitcan be cut during the trimming process.

In order to extrude the slit into rod, a flat pin extrusion bushing canbe used. A trailing ribbon may be attached to the bushing. The ribbonwould prevent curing material across the slit. The ribbon or wire couldbe placed in the rod core and later stripped out leaving a slit. Aninert substance, such as silicone oil, could be coextruded in the centerof the rod to prevent curing across the slit and provide lubrication anda visible target for cannula insertion.

FIGS. 25 and 26 illustrate alternate swaging steps wherein a die 220moving axially toward the housing 200 sages the end region 200a so as toform an annular U-shaped region 200c and the exterior domed peripheralsurface 206c.

The dies 214 or 220 can be formed with various alternate shaped swagingsurfaces 224, as illustrated in FIG. 26, depending on the precise shapeof the end swage which is desired. It will be understood that all suchvariations in the swaging operation are within the spirit and scope ofthe present invention.

The injection site configuration need not be limited to theconfigurations depicted in the figures. Rather, several configurationscould be constructed without departing from the scope of this invention.Any such configuration would provide a flexible pre-slit sealing membercaptured in a housing which provides compression to create a sealagainst pressure and a void region accessible to the sealing membermaterial only when displaced by a blunt cannula piercing member. Onesuch possible configuration is depicted in FIGS. 28 and 29.

In the embodiments of the cannulae described herein, the mid-region andthe tapered distal end region may be alternatively characterized astogether forming at least one tube defining a fluid flow path thereinwith the tube having a distal end region for penetrating the injectionsite.

In preferred contemplated embodiments, the exterior surface of thedistal end region may have a taper angle as small as between one andfifteen degrees.

As shown in FIG. 6, the bayonet locking blunt cannula 82 includes acylindrical hollow protective shield 80 which surrounds a centrallylocated hollow, elongated cylindrical blunt piercing member 98. Thecylindrical blunt piercing member 98 has a total length on the order of3 times the thickness of the septum 52 in order to ensure completepenetration. The cylindrical blunt piercing member 98 has a diameter onthe order of 1/3 the diameter of the septum 52. The blunt piercingmember 98 can slidably engage the septum 52 and extend through thepreformed opening 66. As illustrated in FIG. 13, when the piercingmember 98 slidably engages and pierces the septum 52, the region 52adeforms by expanding into and filling, at least in part, the annularchannel 62.

The bayonet locking cannula 82 shown in FIG. 6 includes a blunt cannulasimilar to that shown in FIG. 16, for example in addition to aprotective shield 80. Protective shield 80 includes an arcuate wall 164that extends approximately 180°-200° from side 166 to flat side 168. Thearcuate wall 164 provides substantial shielding to the blunt piercingmember 98 to maintaining the piercing member 98 in an aseptic conditionby preventing touch contamination prior to its being inserted into thepre-slit septum 52.

Protective shield 80 also includes a bayonet arm 170 which ends in abayonet barb 172 to create an opening or bayonet lock 174. As thebayonet locking cannula 82 is pushed onto the Y-site 36, Y-site arm 76passes through the gap 176 between the end 178 of the bayonet arm andside 168. When the bayonet cannula 82 is pushed as far as possible ontothe Y-site 36, then the Y-site can be rotated with respect to thebayonet lock, causing the side arm 76 to pass over the bayonet barb 172and into the bayonet lock 174.

Because the Y-site 36 is part of an administration set 42 which providesfluid to the patient for a relatively long period of time, it isimportant that leaks be reduced. Leaks may occur at the Y-site if theblunt piercing member is misaligned with the Y-site septum 52 by morethan acceptable tolerance. Such leaks are quite undesirable because ofthe medical implications.

The bayonet lock cannula 82 and the Y-site 36 have three zones ofdocking to provide for correct alignment. These zones of interferenceare indicated on FIG. 19.

The first zone of interference is indicated by A1 and A2 on FIG. 19. Asthe bayonet lock cannula 82 is moved onto the Y-site 36, Y-site arm 76moves through gap 176 between the end 178 of bayonet arm and flat side168. Gap 176 is smaller than the diameter of diameter of Y-site arm 76.For example, the gap 176 may be 0.200" while the diameter Y-site arm is0.220" to create a positive interference of 0.010" per side.

The second zone of interference is indicated by B1 and B2 on FIG. 19.After the piercing member 98 begins to penetrate the opening 66 ofseptum 52, the housing shoulder 182 of the Y-site 36 and the firstinterior mid-region 184 of protective shield 80 engage to createadditional interference and directional guidance between the twocomponents. The housing shoulder 182 and the first interior mid-region184 should have a positive interference of, for example, 0.001" per sideor 0.0025" per side. There should be a maximum positive interferencebetween these two areas of 0.004".

The third zone of interference between the Y-site 36 and the bayonetlock cannula 82 is zone C, indicated by C1 and C2 on FIG. 19, As thebayonet lock cannula 82 continues to move onto Y-site 36, the swagemember 58 holding the septum 52 in compression on Y-site 36 engages thesecond interior mid-region of protective shield 80. The second interiormid-region 188 has a diameter that is smaller than the first interiormid-region 184 which has a diameter that is smaller than the diameter ofthe outer interior region 190. As the swage member 58 contacts thesecond interior mid-region 188, the injection site is now docked andready for engagement within the bayonet lock 174.

The Y-site 36 is engaged by rotating the Y-site arm 76 past the bayonetbarb 172 into the bayonet lock 174 thereby engaging a mechanical lock asindicated by D1 and D2. The dimensions of the Y-site 36 and bayonet lockcannula 82 are such that when the septum 52 is higher than the swagemember 58 the septum 52 must be compressed a slight amount against thecannula 82 to rotate Y-site arm 76 past the bayonet barb 172. When theY-site arm 76 is properly positioned within bayonet lock 174, the septum52 is still compressed a slight amount. The compression of the septum 52and the drag from the cannula 82 against the septum 52 require apredetermined torque to engage the Y-site 36 and to disengage the Y-sitearm 76 from the bayonet lock 174.

The dimensions of the bayonet lock cannula 82 and Y-site 36 used increating the zones of interference must be carefully calculated so thatthe torque is not so large that in engaging or disengaging the Y-site 36from the bayonet lock 174, components adjacent to the Y-site 36 andbayonet lock cannula 174 are disconnected. FIG. 6 shows a bayonet lockcannula 82 bonded to tubing 192 while FIG. 7 shows a bayonet lockcannula 82 having a luer fitting 194 which mates with a luer cap 196which is bonded to tubing 192. American National Standards Institutestandards require that a locking luer fitting must not disconnect until3 inch ounces of force is exerted on it. If the connection ordisconnection of the Y-site arm 76 from the bayonet lock 174 requiresmore force than 3 inch ounces, the luer cap 196 may be accidentallydisconnected from the luer fitting 194.

An alternative embodiment of the bayonet lock cannula 82 is shown inFIG. 8 and generally identified as 82a. Bayonet lock cannula 82aincludes two bayonet arms 170a, 170b, two bayonet barbs 172a, 172b, andtwo bayonet locks 174a, 174 which mate with the two arms of a T-typeconnector with injection site or T-site (not shown).

From the foregoing, it will be observed that numerous variations andmodifications may be effected without departing from the spirit andscope of the novel concept of the invention. It is to be understood thatno limitation with respect to the specific apparatus illustrated hereinis intended or should be inferred. It is, of course, intended to coverby the appended claims all such modifications as fall within the scopeof the claims.

We claim:
 1. A cannula insertion device for being inserted into apre-slit injection site located in a Y-type site housing, said insertiondevice comprising:a tube defining a fluid flow path therein, said tubehaving a distal end region terminating in a blunt piercing end forpenetrating said injection site; said tube defining at least oneaperture in said distal end region through which fluid can flow to orfrom said fluid flow path; and a protective shield at least partiallysurrounding and being spaced apart at a predetermined distance from saidtube, having at least one arcuate wall longitudinally positioned aboutthe distal region of the tube in spaced relation thereto, said arcuatewall defining an open side, and at least one arcuate arm extending fromsaid arcuate wall across a portion of said open side, said arm extendinggenerally circumferentially about the distal region, whereby saidprotective shield may be used to lockingly engage and disengage saidcannula device with the injection site, the arcuate arm of theprotective shield includes a bayonet barb and lock whereby the Y-typesite housing is lockingly engaged and disengaged with the cannula deviceby the rotation of the injection site housing beyond the bayonet barband into the bayonet lock.
 2. A cannula insertion device comprising:acannula defining a fluid path therethrough, the cannula having a distalend portion; and, a protective shield having a first and second portion,the first portion of the protective shield being attached to the cannulaand the second portion at least partially surrounding and being spacedapart from the cannula, the protective shield having twocircumferentially spaced arcuate walls extending longitudinally from theprotective shield, the arcuate walls partially surrounding the cannulaand in spaced relation thereto, the arcuate walls defining two opposedopen sides therebetween, each arcuate wall has an arcuate arm extendingtherefrom in opposite directions from one another, one of each arcuatearm extends partially across separate open sides, each arcuate armextending generally circumferentially about the cannula, each arcuatearm has an enlarged distal end to define a bayonet barb.
 3. The deviceof claim 2 wherein the arcuate walls are essentially 180 degrees apart.4. The device of claim 2 wherein the cannula has a distal end regionhaving a tapered exterior surface terminating in a blunt piercing end,and a midregion having an exterior circumference that is greater thanthe exterior circumference of at least portions of the tapered exteriorsurface, the midregion having a length that is greater than a length ofthe tapered exterior surface.
 5. A cannula insertion device for beinginserted into a Y-type injection site having a side arm and a pre-slitseptum, the insertion device comprising:a tube defining a fluid flowpath therein, the tube having a distal end region having a taperedexterior surface terminating in a blunt piercing end for penetrating theseptum and a midregion having an exterior circumference that is greaterthan the exterior circumference of at least a portion of the taperedexterior surface, the midregion having a length that is greater than alength of the tapered exterior surface; the tube defining at least oneaperture in the distal end region through which fluid can flow to orfrom the fluid flow path; and, a protective shield at least partiallysurrounding and being spaced apart at a predetermined distance from thetube, having at least one arcuate wall longitudinally positioned aboutthe distal region of the tube in spaced relation thereto, the arcuatewall defining an open side, and at least one arcuate arm extending fromthe arcuate wall across a portion of the open side, the arm extendinggenerally circumferentially about the distal region, the arcuate arm hasan enlarged distal end to define a bayonet barb, the open side andarcuate arm being adapted to attach the insertion device to the Y-typeinjection site whereby the protective shield lockingly engages anddisengages with the site by rotating the arcuate arm under the side armafter penetration of the distal end region and insertion of the tubeinto the septum.
 6. A cannula insertion device for being inserted into aY-type injection site having a side arm and a pre-slit septum, theinsertion device comprising:a tube defining a fluid flow path therein,the tube having a distal end region having a tapered exterior surfaceterminating in a blunt piercing end for penetrating the septum and amidregion having an exterior circumference that is greater than theexterior circumference of at least a portion of the tapered exteriorsurface, the midregion having a length that is greater than a length ofthe tapered exterior surface, the tube having an elongate groove on theexterior surface of the distal end region of the tube; the tube definingat least one aperture in the distal end region through which fluid canflow to or from the fluid flow path; and, a protective shield at leastpartially surrounding and being spaced apart at a predetermined distancefrom the tube, having at least one arcuate wall longitudinallypositioned about the distal region of the tube in spaced relationthereto, the arcuate wall defining an open side, and at least onearcuate arm extending from the arcuate wall across a portion of the openside, the arm extending generally circumferentially about the distalregion, the open side and arcuate arm being adapted to attach theinsertion device to the Y-type injection site whereby the protectiveshield lockingly engages and disengages with the site by rotating thearcuate arm under the side arm after penetration of the distal endregion and insertion of the tube into the septum.
 7. A cannula insertiondevice for being inserted into a Y-type injection site having a side armand a pre-slit septum, the insertion device comprising:a tube defining afluid flow path therein, the tube having a distal end region having atapered exterior surface terminating in a blunt piercing end forpenetrating the septum and a midregion having an exterior circumferencethat is greater than the exterior circumference of at least a portion ofthe tapered exterior surface, the midregion having a length that isgreater than a length of the tapered exterior surface, the tube having aplurality of circumferentially spaced elongate grooves on the exteriorsurface of the distal end region of the tube; the tube defining at leastone aperture in the distal end region through which fluid can flow to orfrom the fluid flow path; and, a protective shield at least partiallysurrounding and being spaced apart at a predetermined distance from thetube, having at least one arcuate wall longitudinally positioned aboutthe distal region of the tube in spaced relation thereto, the arcuatewall defining an open side, and at least one arcuate arm extending fromthe arcuate wall across a portion of the open side, the arm extendinggenerally circumferentially about the distal region, the open side andarcuate arm being adapted to attach the insertion device to the Y-typeinjection site whereby the protective shield lockingly engages anddisengages with the site by rotating the arcuate arm under the side armafter penetration of the distal end region and insertion of the tubeinto the septum.
 8. A cannula insertion device for being inserted into aY-type injection site having a side arm and a pre-slit septum, theinsertion device comprising:a tube defining a fluid flow path therein,the tube having a distal end region having a tapered exterior surfaceterminating in a blunt piercing end for penetrating the septum and amidregion having an exterior circumference that is greater than theexterior circumference of at least a portion of the tapered exteriorsurface, the tube exterior surface has a matte finish, the midregionhaving a length that is greater than a length of the tapered exteriorsurface; the tube defining at least one aperture in the distal endregion through which fluid can flow to or from the fluid flow path; and,a protective shield at least partially surrounding and being spacedapart at a predetermined distance from the tube, having at least onearcuate wall longitudinally positioned about the distal region of thetube in spaced relation thereto, the arcuate wall defining an open side,and at least one arcuate arm extending from the arcuate wall across aportion of the open side, the arm extending generally circumferentiallyabout the distal region, the open side and arcuate arm being adapted toattach the insertion device to the Y-type injection site whereby theprotective shield lockingly engages and disengages with the site byrotating the arcuate arm under the side arm after penetration of thedistal end region and insertion of the tube into the septum.
 9. Thedevice of claim 8 wherein the matte finish is located at the tube distalend region.